Torque transmitting arrangement with axial magnetic bias



March 10, 1970.

Filed Oct. 7, 1968 A. H. VIETHS TORQUE TRANSMITTING ARRANGEMENT WITH AXIAL MAGNETIC BIAS 2 Sheets-Sheet 1.

v22 70 l 44 48 65a o I 62 56 MOTOR 56 1*; SSSE- 4e :53 20 95 50 CONTROL A 74 I Q I 0 1 swn-cH HVVENTOA ALMA/V A! VIEW-l5 A Wore/v5 y March 10, 1970 "A. H. VIETHS I 3,499,496

TORQUE TRANSMITTING A RRANGEMENT WITH AXIAL MAGNETIC BIAS '2 Sheets-Sheet 2 Filed Oct. 7. 1968 INVENTOR ALMA/v VIETHS 539 United States Patent O US. Cl. 173-19 9 Claims ABSTRACT OF THE DISCLOSURE There is disclosed herein an improved torque transmitting arrangement particularly adapted for driving a tapping tool to provide a threaded hole in a workpiece. A tubular body member is provided having a tool end cap and a drive end cap to define therein a body cavity. Drive means for rotating the body member is coupled to the drive end cap. The tubular body member has a peripherally extending slot means in the walls thereof adjacent the drive end cap and an axially extending slot means in the walls thereof adjacent the tool end cap. Positioned within the body cavity is a drive assembly comprising a drive base plate having drive tabs extending into the peripheral slot and a drive connecting member coupled thereto and the drive connecting member has a plurality of alternating pole magnetic pole pieces. A tool assembly is also positioned in the cavity and has a tool baseplate with tool tabs extending into the axially oriented slot means adjacent the tool end cap and has a tool connecting member, coupled thereto that is similar to the drive connecting member, and the tool connecting member has the same plurality of alternating pole magnetic pole pieces. There is also provided a tool shaft coupled to the tool baseplate and extending through an aperture in the tool end cap to regions external the body member. A tool, such as a tapping tool, can be coupled to the tool shaft to provide a threaded hole in a workpiece. When the body member is rotated, there is initially relative motion between the body member and the drive assembly until the drive tabs engage the side walls of the peripheral aperture, at which time the entire drive assembly commences rotation with the body member. When the body member is rotated, the tool assembly always rotates with the body member but can move reciprocatingly in axial directions as the tool tabs slide in the axially oriented slot. For rotation in a first direction, the magnetic pole pieces of the drive connecting member and the tool connecting member are aligned so that they are repelled and, therefore, the tool assembly moves axially outwardly to engage the workpiece, and the rotation of the body member provides the necessary rotational movement for providing the torque necessary to tap the hole. When the hole has been tapped to a preselected depth, a signal is generated to reverse direction of rotation of the motor, and there is, once again, relative motion of the drive assembly with respect to the body member until the opposite side wall of the peripheral slot engages the drive tab means, but the tool drive assembly continuously rotates therewith. When the opposite wall of the peripheral slot engages the drive tab means, the magnetic pole pieces in the drive connecting member are aligned with unlike magnetic pole pieces of the tool connecting member and therefore a magnetic attraction exists for this attract position of the drive connecting member, and the tool drive assembly is axially moved away from the workpiece and towards the drive connecting member.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to the torque transmitting art and more particularly to an improved torque transmitting e ICC drive arrangement, particularly adapted to providing the necessary torque for rotating a tap to generate a threaded hole.

Description of the prior art In many applications it is desired to provide, sequentially, a plurality of tapped holes in one or more work pieces. It is known that in providing a threaded hole by means of a tap, there is generally first provided a hole of a preselected size in the workpiece, and the tap does not perform any function of drilling the hole, but rather only the cutting of the threads in the walls defining the hole. Therefore, little or no axial force is required to push or force the tap into the hole. But rather, during rotation, the screw thread action of the tap draws the tap into the hole. Therefore, the only force required is a retational force applied to the tap which, for convenience, may be considered as a torque of a preselected magnitude applied to the tap during the thread cutting in the workpiece.

While the utilization of the forces associated with mag netic fields have been utilized in the past for various coupling and clutch driving arrangements, applicant is unaware of any arrangement that utilizes the magnetic forces for providing an automatic withdrawal of a tap when it has completed the tapping of a hole in the workpiece and has been disengaged therefrom so that a new workpiece or the same workpiece oriented to a different position may be placed thereunder as well as the initial outward movement of the tap from a retracted position to the engagement of the tap in the hole in the workpiece that is to be threaded. That is, in one position it is desired to have magnetic attraction means providing opposite polarity magnetic pole pieces between the two connecting members and in a second position an outwardly directed repelling source by providing an alignment of like pole magnetic pole pieces to move the tap outwardly to engage the hole to be tapped.

SUMMARY OF THE INVENTION Accordingly, it is an object of applicants invention herein to provide an improved torque transmission arrangement.

It is another object of applicants invention herein to provide an improved torque transmitting arrangement in which magnetic sources are provided to extend and retract a tool.

It is yet another object of applicants invention herein to provide a torque transmitting arrangement that is comparatively inexpensive to fabricate and comparatively economical to maintain and operate.

The above and other objects of applicants invention herein are achieved, according to one aspect of applicants invention, by providing a closed tubular body member having a drive end cap coupled to a first end thereof and tool end cap coupled to a second end thereof. First walls of the tubular body member define a peripherally extending first slot having a preselected length adjacent the drive end cap and second walls define an axially extending second slot adjacent the tool end cap.

There is a drive baseplate positioned in the body cavity defined by the tubular body member, tool end cap and drive end cap, and the drive baseplate is adjacent the drive end cap and has drive tab means extending into the first slot so that the drive baseplate is driven by the tubular body member when the drive tab means is adjacent the side walls thereof, but allows relative rotary motion when the direction of rotation of the body member is changed from a first to a second opposite direction until the opposite side wall engages the drive tab means. A drive connecting member is coupled to the drive base plate in the body cavity and moves therewith. The drive connecting member has a plurality of sequentially alternating pole magnetic pole pieces in a preselected array and is in an attracting position for the drive tab means in driven engagement with a first of the walls defining the peripherally extending slot and a second repel position for the drive tab means in driven relationship to the opposite side wall in the peripherally oriented slot.

A tool baseplate is also provided, mounted in the body cavity, and it is adjacent the tool end cap and is adapted to move in axially reciprocating relative motion with respect to the body member. The tool baseplate has a tool tab means positioned in the axially oriented, second slot in driven relationship to the walls thereof, and the tool baseplate always rotates with rotation of the body member, regardless of the direction thereof, but is free to move relative to the body member in axial directions as the tool tab slides in the axially oriented slot.

A tool connecting member, which is similar to the drive connecting member, is coupled to the tool baseplate and also has the same plurality of sequentially alternating pole magnetic pole pieces and the same preselected array and for the drive. connecting member in the attracting position the plurality of sequentially alternating pole magnetic pole pieces of the drive connecting member are aligned with opposite poles of the sequentially alternating magnetic pole pieces of the tool connecting member and, therefore, the tool connecting member and tool baseplate are attracted toward the drive connecting member and therefore move axially as a unit toward the drive connecting member to within a preselected distance thereof.

When the direction of rotation of the body member is reversed, there is at first relative rotary motion between the tubular body member and the drive base plate until the opposite side wall of the peripherally oriented slot engages the drive tab means. However, the tool baselate rotates with the body member, and therefore there is a relative rotary movement of the magnetic pole pieces of the drive connecting member with respect to the magnetic pole pieces of the tool connecting member. The length of the peripherally oriented slot is such that exactly one pole piece relative movement takes place during each reversal of direction of rotation of the body member from one driving condition with respect to the drive tab means to the other and, therefore, when such reversal of direction takes place, the sequentially alternating pole magnetic pole pieces of the drive connecting member are then aligned with like magnetic poles of the tool connecting member. Since the pole pieces of the drive connecting member are so aligned with like pole pieces in the tool connecting member, there is a repelling force therebetween, and the tool connecting member and tool baseplate are moved axially outwardly away from the drive connecting member.

There is provided a tool shaft coupled to the drive baseplate, and the tool shaft extends through the aperture in the tool end cap and a tool means, such as a tap, is connected to the tool shaft. When the tap is just positioned to start tapping a hole in the workpiece, it is at a position in its outward travel away from the drive connecting member but less than the maximum. In this position, the tap commences cutting threads into the drilled hole in the workpiece and the torque transmitting arrangement transmits the necessary torque to drive the tap, substantially all axial force being provided solely by the thread action of the tap in the hole pulling the tap axially. The repelling force of the magnets is several orders of magnitude less than the thread forces, When the direction of control of the motor is reversed, in response to detection means measuring how far the tap has progressed into the hole, the drive connecting member is switched into attract position by the reversal of direc tion of rotation and the tap backs out of the now threaded hole due to the thread action, the torque transmitting arrangement of applicants invention merely providing the necessary torque for rotating the tap. When the tap is free of the hole, the attractive magnetic forces snap the entire tool connecting member, tool baseplate, tool shaft and tap, towards the drive connecting member, where it remains until the direction of the rotation of the body member is changed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1; n

FIG. 3 is a sectional view taken along the line 3.-3 of FIG. 1;

.FIG. 4 is a sectional view taken along the line 44 of FIG. 2;

FIG. 5 is a sectional viewtaken along theline 5. 5.of FIG. 3;

FIG. 6 is a partial sectional view taken along the line 66 of FIG. 4; and

FIG. 7 is a partial sectional view taken along the line 7-7 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, there is illustrated the structure comprising one embodiment of applicants invention of an improved torque transmitting arrangement, generally designated 10. As shown on FIG. 1, applicants improved torque transmitting arrangement 10 is generally comprised of a closed tubular body member 12 having a drive end 14 and a tool end 16. Tubular body member 12 has an external wall surface 18 and an internal wall sur face 20.

A drive end cap 22 is detachably coupled to the drive end 14 of the tubular body member 12 by, for example, the removable screws 24.

A tool end cap 26 is detachably coupled to the tool end 16 of tubular body member 12 by, for example, other removable screws 28.

The internal wall surface 20 of the tubular body member 12, the internal surface 30 of drive end cap 14 and internal surface 32 of tool end cap 16 define a body cavity 34.

The tubular body member 12 has first wall portions 36 defining a first peripherally extending slot means 38 adjacent the drive end 14 thereof. The tubular body member 12 also has second wall portions '40 defining a second axially oriented slot means 42 adjacent the tool end 16 thereof.

A drive means comprising a reversible, electrically operated motor 44 hasa drive shaft 46 coupled to the drive end cap 22 so that rotation of the reversible electric motor 44 in the directions indicated by the arrow 48 rotates the drive end cap 22 body member 12 and tool end cap 26 in the same direction therewith. i

A tool shaft 50 extends from the body cavity 34 to regions external the tubular body member 12 and has a tool connecting end 52, to which there is attached an appropriate tool 54, which, for example, may be a tap for providing a threaded hole in a workpiece (not shown). The tool shaft 5 0 has an arm member 56 connected thereto in operable relation to a switch 58. The switch 58 is connected to a control 60 on a motor 44. When the arm means 56 contacts the switch 58, an information signal'is generated therein and transmitted to the control 60. The control 60, upon receipt of the information signal reverses the direction of rotation of the drive shaft 46 from the direction in which it has been turning.

The tool shaft 50 is adapted to move reciprocatingly with respect to the tubular body member 12 in the direction indicated by the arrow 62. The techniques utilized by applicant for providing control over the movement of the tap 54 in the directions indicated by the arrow 62 are described below in greater detail.

It will be appreciated, of course, that when the tool 54 is a tap, virtually no axial force in the direction indicated by the arrow 62 is required to drive the tap into the hole in the workpiece that is to be threaded or to remove same. That is, only a torque transmission to rotate the tool shaft in the directions indicated by the arrow 48, depending upon whether it is a right-hand or a left-hand thread, is required to provide the threads. Thus, applicants improved torque transmitting arrangement of the invention herein transmits the necessary torque as provided by the motor 44, to the tap 54 to make the threads and to remove the tap after the completion of the threading operation by reversal of the direction of rotation.

As shown more clearly in FIGS. 2, 3, 4, 5, 6 and 7, a drive baseplate 64 is positioned in the body cavity 34 for relative rotational movement about the axis 66 relative to the body member 12 as well as rotational movement with the body member 12 when the body member 12 is driven by the motor means 44. The drive baseplate 64 has a pair of oppositely disposed drive tab members 6811 and 68b which are positioned in the first slot 38 defined by the first walls 36 in the tubular body 12. When first wall portions 70 of the walls 36 defining the peripherally extending aperture 38 engage the tab means 68a and 68b, the body member 12 drives the drive baseplate 64 in the direction indicated by the arrow 72 shown in FIG. 2.

When the direction of rotation of the body member 12 is reversed, there is, at first, no actual rotation of the drive baseplate 64, but only relative rotation thereof relative to the tubular body member 12 until the second wall portions 74 engage the tab members 68a and 68b to drive the drive baseplate in a direction opposite to the rotary direction indicated by the arrow 72.

A drive connecting member 76 is positioned within the body cavity 34 and is coupled by screw means 78 through the drive baseplate 64, and the drive connecting member moves in rotary directions with the drive baseplate 64 as the drive baseplate 64 is rotated by the tubular body member 12. The drive connecting member 76 is provided with a base portion 80 through which the screw means 78 extends for coupling the drive connecting member 76 to the drive baseplate 64. The drive connecting member has a first plurality of sequentially alternating pole magnetic pole pieces 82, 84, 86, 88, 90 and 92. In a preferred embodiment of applicants invention, the number of separate pole pieces is an even number in the plurality of thereof. The magnetic poles 82, 86 and 90 are north magnetic poles, and the alternating magnetic poles 84, 88 and 92 are south magnetic poles. Applicant has found that the entire drive connecting member may be fabricated, conveniently, from a material such as Alnico or any other permanent magnet-type material.

When the drive tabs 68a and 6812 are in contact with the wall portion 70 of the aperture 38 for rotation of the drive baseplate 64 and drive connecting member 76 in the direction indicated by the arrow 72, this may be construed as an attracting position. When the drive tab members 68a and 68b are in contact with the wall 74 for driving relationship therewith for rotation of the tubular body member 12 in direction opposite to that illustrated by the arrow 72, the drive connecting member may be considered to be in a repel position. The significance of the attract and repel position of the drive connecting member 76 is more fully described below.

To minimize abrasive wear on the permanent magnet drive connecting member 76, applicant has found it advantageous to provide an insert ring member 93 intermediate the external surfaces of the drive connecting member 76 and the internal surface 20 of the tubular body member 12 to act as a bushing or bearing surface for the periods of relative rotary motion between the drive connecting member 76 and the tubular body member 12 when the direction of rotation of the motors 44 is reversed. As shown more clearly in FIG. 6, the ring member 94 rotates with both the relative rotary motion of the drive baseplate 64 and drive connecting member 76, as well as rotary motion with the body member 12.

There is also positioned within the body cavity 34 a tool baseplate 96 adjacent the tool end cap 26 and the tool baseplate 96 is adapted to move reciprocatingly in the body cavity 34 in the directions indicated by the arrow 62. The reciprocating axial relative motion between the body member 12 and the tool baseplate 96 occurs under the influence of magnetic interaction as described below. The tool baseplate 96 has tool tab members 98a and 98b positioned in the second, axially oriented slot 42 defined by the walls 40. During the relative reciprocating motion of the tool baseplate 96, the tab members 98a 9812 move reciprocatingly in the second slot 42.

The side wall portions 100 and 102 of the second slot 42 are in driving relationship to the tool tabs 98a and 98b so that rotation of the body member 12 in the directions indicated by the double-ended arrow 48 drives the tool baseplate 96 at the same rate and the same direction. During such rotation, of course, the tool baseplate 96 may move reciprocatingly in the direction indicated by the arrow 62.

A tool connecting member 104 is coupled by screw means 106 to the tool baseplate 96. The tool connecting member 104 is similar to the drive connecting member 76 shown in FIGS. 2 and 4. That is, it may be comprised of a base portion 108- through which the screw means 106 projects for coupling to the tool baseplate 96 and a plurality of sequentially alternating pole magnetic pole pieces. The number in the plurality of alternating pole magnetic pole pieces as shown at 110, 112, 114, 116, 118 and is the same even number of pole pieces as shown on the drive connecting member 76 and, in this embodiment of applicants invention, the plurality comprises six alternating magnetic pole pieces. That is, the pole pieces 110, 114 and 118 are north poles, and the sequentially alternating pole pieces 112, 116 and 120 are south poles.

For the positions shown in FIGS. 4 and 5, the drive connecting member 76 is in a repel position and hence the like magnetic poles of the drive connecting member 76 and the tool connecting member 104 are aligned so that the magnetic flux therebetween tends to move the tool conecting member 104 axially outwardly from the drive connecting member 76.

The length of the first peripherally oriented slot 38 is equivalent to the angular spacing between adjacent pole pieces so that when the direction of rotation of the motor 44 is changed to the opposite, and the side wall 74 of the slot 38 is in engagement with the tab member 68a and 68b, there has been a relative rotary movement between the drive connecting member 76 and the tool connecting member 104 equivalent to one magnetic pole spacing. When this occurs, unlike magnetic poles of the drive connecting member and the tool connecting member are aligned, and the drive connecting member is in the attract position. In this condition there is an attraction between the drive connecting member 76 and the tool connecting member 104 so that the tool connecting member 104 and tool baseplate 96 are moved axially towards the drive connecting member 76 as the tool tabs 98a and 98b slide in the second slot means 42.

The tool end cap 16 has wall 120 defining an aperture 122 through which the tool shaft 50 projects to regions external the body cavity 34. Thus, the axial movement of the tool baseplate 96 and tool connecting member 104 moves the tool shaft 50 in the same axially reciprocatingly motion and, consequently, the tool 54 is moved reciprocatingly in and out of contact with the workpiece. The tool connecting member 104 may be Alnico or any other similar permanent magnet material and, in a preferred embodiment of applicants invention, to prevent abrasion of the permanent magnet, applicant prefers to provide a second sleeve means 124 adjacent the internal walls 20 of the tubular body member 12 and surrounding the external surfaces of the tool connecting member 104. The second sleeve means 124 acts as a bearing for movement with the tool connecting member during the reciprocating motion of the tool connecting member 104 relative to the tubular body member 12.

In a preferred embodiment of applicants invention, :fipplicant prefers that for the condition of the drive connecting member 76 in the attract position and the tool connecting member 104 retracted to a position as close to the drive connecting member 76, there should be a spacing between the ends of the magnetic pole pieces on the drive connecting member 76 and the magnetic pole pieces on the tool connecting member 104. One way of providing this is to have either the first ring member 94 or second ring member 124 extend axially beyond the ends of the drive connecting member 76 or tool connecting member 104, respectively, as illustrated in FIGS. 4 and 5.

This concludes the description of applicants invention of an improved torque transmitting arrangement. From the above it can be seen that applicant has provided a positively driven arrangement for axial rotation of the tool member and a utilization of the effects of a magnetic field for reciprocating motion of the tool member.

What is intended to be claimed as new and desired to be secured by Letters Patent of the United States is:

I. A torque transmitting arrangement comprising, in combination:

a closed, tubular body member having a drive end and a tool end;

a drive end cap coupled to said drive end of said body member;

a tool end cap coupled to said tool end of said body member, and said tool end cap having walls defining an aperture therethrough, and said tubular body member, said drive end cap and said tool end cap defining a body cavity;

said tubular body member having first walls defining a peripherally extending first slot having a first preselected length, adjacent said drive end thereof, and second walls defining an axially extending second slot, having a second preselected length adjacent said tool end thereof;

a drive base plate in said body cavity of said body member adjacent said drive end cap for relative rotational movement therein and rotational movement therewith, and having a drive tab portion extending through said first slot in driven relationship to said first walls thereof;

a drive connecting member coupled to said drive baseplate in said body cavity for movement therewith in said body cavity and said drive connecting member having a first plurality of sequentially alternating pole magnetic pole pieces disposed in a preselected first pattern array, and having a first attracting position for said drive tab in a first position in said first slot for rotation of said body member in a first direction, and a second repel position for said drive tab in a second position in said first slot for rotation of said body member in a second direction opposite said first direction;

a tool base plate mounted in said body cavity adjacent said tool end cap thereof for axially reciprocating relative motion therein and rotational movement therewith, and having a tool tab positioned in said second slot in driven relationship to said second walls thereof;

a tool connecting member coupled to said tool baseplate in said body cavity for movement therewith and in magnetic field interaction relationship with said drive connecting member for at least the condition of said drive connecting member in said attracting position, and said tool connecting member having said first pluralityof sequentially alternating pole magnetic pole pieces disposed in said first preselected pattern array, and opposite pole magnetic pole pieces of said drive connecting member and said tool connecting member in alignment for said drive connecting member in said attracting position, and like pole magnetic pole pieces of said drive connecting member and said tool connecting member in alignment for said drive connecting member in said repel position;

a tool shaft coupled to said tool base plate for axially reciprocating motion therewith and extending through said aperture in said tool end cap to regions external said body members; and,

drive means for selectively rotating said body member in said first direction and said second direction.

2. The arrangement defined in claim 3- wherein:

said magnetic pole pieces of said tool connecting member are spaced a first preselected distance from said magnetic pole pieces of said drive connecting memher for said drive connecting member in said attract position.

3. The arrangement defined in claim 1 wherein:

said first plurality comprises an even number of magnetic pole pieces and said preselected first pattern array comprises an equal angular radial distribution of said magnetic pole pieces; and,

said preselected peripheral length of said first slot comprises a length corresponding to the angular spacing between adjacent magnetic pole pieces of said drive connecting member.

4. The arrangement defined in claim 3 wherein said drive means comprises:

a reversible motor means having a drive shaft coupled to said drive end cap of said body member for rotating said body member and thereby rotatingly driving said drive connecting member and said tool shaft;

detection means for detecting axial movement of said drive shaft and generating an information signal in response thereto;

control means for receiving said information signal and connected to said reversible motor means for controlling the direction of rotation of said motor means in response thereto.

5. The arrangement defined in claim 4 'wherein said detection means comprises:

an arm means coupled to said tool shaft external said body member; and,

a switch means in operative engagement to said arm means for the condition of said tool shaft at a preselected axially extended position, and said switch means connected to said control means to transmit said information signals thereto.

6. The arrangement defined in claim 5 wherein:

said magnetic pole pieces of said tool connecting member are spaced a first preselected distance from said magnetic pole pieces of said drive connecting member for the condition of said drive connecting member in said attract position.

7. The arrangement defined in claim 3 and further drive sleeve means intermediate internal walls of said tubular body member and said drive connecting member and preselected portions of said drive baseplate, and tool sleeve means intermediate said internal Walls of said tubular body member and said tool connecting member and preselected portions of said tool baseplate.

8. The arrangement defined in claim 7 wherein:

said magnetic pole pieces of said tool connecting member are spaced a first preselected distance from said magnetic pole pieces of said drive connecting member for said drive connecting member in said attract position.

9. The arrangement defined in claim 7 wherein said drive means comprises:

a reversible motor means having a drive shaft coupled to said drive end cap to rotate said body member and thereby rotatingly drive said drive connecting member and said tool shaft;

detection means for detecting axial movement of said drive shaft and generating an information signal in response thereto;

control means for receiving said information signal and coupled to said reversible motor means for controlling the direction of rotation of said reversible motor means in response to said information signal; and,

ber are spaced a first preselected distance from said magnetic pole pieces of said drive connecting member for said drive connecting member in said attract position.

References Cited UNITED STATES PATENTS 2,622,372 12/1952 Moulden 173-19 X 2,790,095 4/1957 Peek et al. 310103 2,943,216 6/1960 Spodig 310-103 ERNEST R. PURSER, Primary Examiner US. Cl. X.R.

said magnetic pole pieces of said tool connecting mem- 15 77-329; 173150 

